Low TDS water has a low concentration of total dissolved solids, meaning that it’s less likely to contain impurities like chemicals, heavy metals, and minerals.
That technically means that low TDS water is safer to drink than normal tap water. But are there any side effects of drinking water with a low total dissolved solids count?
We’ve shared everything you should know in this guide.
📌 Key Takeaways:
- Low TDS water is typically produced by a reverse osmosis system and contains low-to-no concentrations of dissolved solids.
- All the dissolved substances in water are classed as TDS, including chemicals, metals, salts, minerals, and more.
- Potential side effects of low TDS in drinking water are linked to reduced mineral intake and increased likelihood of heavy metals leaching.
Table of Contents
🔎 What Is TDS And How Is It Measured?
Feel free to skip straight to the next section if you don’t want a recap of TDS and how it affects drinking water quality.
Total dissolved solids (TDS for short) is a measure of the dissolved minerals, salts, metals, chemicals, and all other impurities in water.
TDS doesn’t only refer to the harmful contaminants in water – it also refers to the healthy minerals and salts found naturally in drinking water.
Some impurities that contribute to TDS include:
- Fluoride
- Calcium
- Magnesium
- Sodium
- Potassium
- Cadmium
- Arsenic
- Sulfates
- Zinc
- Copper
- Chromium
- Nickel
- Iron
- Manganese
- Nitrate
- Chloride
Generally, the higher the TDS level, the more likely it is that the water quality is poor. Excessive dissolved solids in water may indicate that there’s a dangerously high concentration of certain contaminants (although you can’t confirm this without testing your water to see exactly which impurities are contributing to the TDS).
So, how is TDS measured?
The most common way to measure total dissolved solids is with a TDS meter, which gives a TDS reading in parts per million (PPM).
Here are the TDS drinking water guidelines outlined by the World Health Organization (WHO):
| Less than 300 PPM | Excellent |
| 300-600 PPM | Good |
| 600-900 PPM | Fair |
| 900-1,200 PPM | Poor |
| 1,200 PPM+ | Unacceptable |
🤔 Is Low TDS Water Harmful?
Low TDS water isn’t directly harmful, but you should still be aware of some of the side effects of drinking water with a low dissolved solids concentration.
The WHO says that a TDS level of 300 PPM is excellent, but doesn’t recommend water with extremely low TDS levels (100 PPM or below) due to its flat, insipid taste.
🩺 Potential Side Effects Of Drinking Low TDS Water
Let’s look at the potential side effects of drinking water with a low TDS level.
1) Reduced Intake Of Healthy Minerals
Normal drinking water provides about 20% of your dietary intake of dissolved calcium and magnesium minerals. So, it stands to reason that if you drink water containing little to no minerals – AKA low TDS water – you’ll miss out on around 20% of calcium, magnesium, and other healthy minerals and salts in your diet.
Some of the potential health effects of calcium and magnesium deficiencies include muscle cramping, numbness, fatigue, weakness, loss of appetite, and abnormal heart rhythms.
However, as long as you eat a healthy, balanced diet, you’re unlikely to become deficient in these essential minerals simply by drinking water with a low TDS level.
2) Increased Likelihood Of Metal Leaching
Water with a very low TDS is “hungry” because of its lack of impurities, so it’s more likely to leach metals like copper from your water pipes.
Human consumption of low levels of most heavy metals is considered safe, but drinking elevated levels of metals over time may have a variety of long-term health effects.
In a worst-case scenario, heavy metals toxicity may cause reduced energy levels, damage to the lungs, liver, and brain, and altered blood composition.
3) May Trigger Acid Reflux
As we mentioned above, water with low TDS concentrations is typically mildly acidic because it’s lacking the impurities that increase alkalinity.
According to a number of sources online, someone who is prone to acid reflux may be more likely to experience symptoms of reflux and heartburn due to drinking low TDS water, due to imbalanced pH in the body.
However, we could only find anecdotal evidence of this, and no clinical studies, so we can’t confirm that TDS in water has any correlation to acid reflux.
4) Potential Hydration Issues
Low-TDS water lacks the dissolved salts and minerals that give water a pleasant alkaline taste. You might find this water less appealing, and drink less water as a result.
Experts estimate that around 75% of Americans are chronically dehydrated – and that’s without taking TDS in water into account. If you struggle to drink enough water as it is, you might find it even more difficult to meet your daily water needs with low TDS water.
Side effects of mild dehydration include headache, dizziness, and fatigue, and more serious cases may lead to low blood pressure, confusion, and heatstroke.
📖 How To Improve Low TDS Levels In Water
So, while low TDS water isn’t typically considered a health hazard, there are still some potential side effects to be aware of.
Luckily, there are a few things you can do to make this water healthier and reduce the likelihood of the above health effects.
These are:
- Buy a reverse osmosis system with a remineralization filter – Many modern reverse osmosis systems have a final-stage remineralization filter that adds healthy minerals back into water before it’s dispensed for drinking.
- Add mineral drops to your water – You can buy mineral drops online to add to your water. This will have the same effect as a remineralization filter.
If you enjoy the benefits of low TDS water but you want to avoid the potential side effects, remineralizing your water is the simplest solution.